Dirtiest gun I ever owned....but I have gotten used to cleaning it. Most I ever went was 500 rounds before cleaning. Usually I clean it at 200-300 rounds .
If you take the silver feed ramp and silver bolt assembly out of the gun, then soak them in Hoppes#9 overnight ,they will clean up nicely for you.

I have one of the new Ruger PC-9's NIB that I took on a tade and it appears to be a real piece of work. It takes the Glock clips. I wonder if they have to be cleaned like the older PC-9's?

Tough to say . I have one of the originals ,a PC4, from 1997, but it is totally new design,now the PCC resembles the PC9/PC4, but it is all new.
Hopefully it is built Ruger tough?
I love my PC4 and my Mini 14.